0000000000764517
AUTHOR
K. Hartmann
Crystallization of Light-Harvesting Complex II From Vicia Faba (Fabaceae)
The most abundant chlorophyll binding complex in plants is the intrinsic light-harvesting complex II (LHC II), comprising about half of the total chlorophyll in thylakoid membranes. The structure of LHC II has been determined by electron crystallography, providing a three-dimensional map at 3.4 A (1). Nevertheless, high-resolution structure based on x-ray crystallography is still missing because of the lack of highly ordered 3-D crystals. While delipidation of membrane proteins suitable for high-quality 3-D crystals seems to be a prerequisite, in case of LHC H delipidation leads to a loss of the ability to crystallize. So far, standard purification methods like chromatography have been proo…
Nonexponential 2H spin-lattice relaxation as a signature of the glassy state
Abstract High-precision measurements of 2H spin-lattice relaxation on several molecular glass-forming liquids have been performed. As a general feature the following can be stated: At temperatures more than ten to twenty degrees above the calorimetric glass transition temperature Tg the 2H spin-lattice relaxation is exponential; below that temperature regime the relaxation is nonexponential. This crossover from exponential to nonexponential magnetization recovery implies that no common spin temperature caused by spin diffusion exists in a 2H glass. This contrasts 1H spin-lattice relaxation which is found to be strictly monoexponential throughout. The occurrence of nonexponential 2H relaxati…